Factors associated with participation in an ongoing national catch-up campaign against rubella: a cross-sectional internet survey among 1680 adult men in Japan

Using Regular High-Quality Serosurveys to Identify and Close National Immunity Gaps-Measles and Rubella Elimination in Japan

In Japan, periodic measles outbreaks occurred mainly among young children under the routine immunization program with one dose of the measles-containing vaccine (MCV). A second dose of MCV was introduced in 2006. During a nationwide measles resurgence in 2007-2008, the most affected age group was teenagers. The national serological surveillance for vaccine-preventable diseases made it clear that there was a measles immunity gap among teenagers who had not received a second dose of MCV. To fill this immunity gap, nationwide non-selective supplementary immunization activities (SIAs) were carried out as a five-year program from April 2008 to March 2013 by providing an opportunity to be vaccinated with the measles and rubella vaccine during the first year of junior high school (12-13 years old) and the last year of high school (17-18 years old). The SIA was conducted with the strong involvement of local governments in charge of vaccination delivery and collaboration between the health and education sectors. Japan was verified as achieving measles elimination in 2015 and this has been sustained to date. The challenge of rubella elimination following a similar strategy of a serological diagnosis of an immunity gap and targeted vaccination is also discussed.

Gender differences in responses to an altruistic message regarding rubella vaccination

Background

The supplementary immunization activity (SIA) for the rubella vaccination of adult men born between 1962 and 1978 began in 2019 in Japan because of a vaccine gap in the cohort, as vaccination was not mandatory for those born in that period. However, SIA coverage remains low, despite an active campaign and financial support.

Methods

We conducted a randomized controlled study based on a 2 (scenario: self-vaccination, child vaccination) × 2 (message: self-interest, group-interest) factorial design, using a Japanese online panel. Participants with children were assigned to the child vaccination scenario in Intervention 1, whereas others were assigned to the self-vaccination scenario. After Intervention 1, all participants were given the same information about rubella. In Intervention 2, participants assigned to self-interest messages received a message emphasizing the risk of rubella, and those assigned to group-interest messages received a message emphasizing herd immunity. After Intervention 2, we evaluated the effects using a questionnaire.

Results

Among the 2,206 participants, information regarding rubella was evaluated as more reliable in the group-than in the self-interest message condition, especially among women. Women evaluated the necessity of rubella vaccination for adult men and women to be higher in the child-vaccination scenario and group-interest messages. However, no differences were found among men. By contrast, men exposed to the self-interest message positively evaluated the reliability of the rubella explanation.

Conclusion

The findings indicate that emphasizing self-interest messages is more effective for men in promoting herd immunity against rubella.

Identifying the population susceptible to rubella in Japan, 2020: Fine-scale risk mapping

BACKGROUND

Rubella remains a public health challenge in Japan, impeding the attainment of herd immunity. Despite vaccination efforts since 1976, persistent outbreaks reveal a susceptibility gap in male adults born before 1995. Seroepidemiological surveys are pivotal in evaluating population immunity and identifying at-risk groups.

METHODS

This study aims to pinpoint high-risk areas for potential rubella outbreaks in Japan by merging seroepidemiological data from 2020 with population census information. Various data sources, including spatial demographic data, reported rubella and congenital rubella syndrome (CRS) cases, and traveler lodging statistics, were employed. Geospatial information for Japan's 230,300 small geographic areas was analyzed, and HI (hemagglutination inhibition) titers were examined by age and sex. Seroconversion was defined as an HI titer ≥ 1:32 or 1:16, indicating protective immunity. Geospatial maps illustrated the distribution of susceptible individuals per square kilometer, emphasizing high-risk urban areas like Tokyo and Osaka. Demographic shifts in the working-age population were assessed.

RESULTS

Susceptible individuals cluster in densely populated urban centers, persisting despite demographic changes. The study highlights areas at risk of increased susceptibility, particularly with an HI titer cut-off of 1:16. Foreign travelers pose potential rubella importation risks as travel volume to Japan rises. To prevent epidemics and congenital rubella syndrome burden, achieving and sustaining herd immunity in high-risk areas is crucial.

CONCLUSIONS

This study offers a comprehensive assessment of vulnerability in densely populated Japanese regions. Integrating population statistics with seroepidemiological data enhances our understanding of population immunity, guiding resource allocation for supplementary vaccination planning. To avert rubella epidemics, high-risk locations must bolster indirect protection through herd immunity, ultimately preventing congenital rubella syndrome.

Trends in Participation in Rubella Antibody Testing among Working-Aged Men during Annual Health Check-Ups from 2019 to 2022 in Japan

In 2019, the Japanese government established a scheme for rubella antibody testing of men born between 1962 and 1978 during workplace health check-ups. However, the use of vouchers for rubella antibody testing was limited. Health check-up data analyses are needed to determine the reason why rubella antibody testing is not widely used. In this study, we aimed to describe changes in rubella antibody test-taking behavior during health check-ups during the first 3 years of the rubella catch-up campaign in Japan. In 2019, 2020, and 2021 (2020 in some areas) vouchers were sent to men born during the fiscal years 1972-1978, 1966-1971, and 1962-1965, respectively. We calculated the prevalence in men born between 1962 and 1978 who underwent rubella antibody testing during mandatory health check-ups under the Industrial Health and Safety Act. Rubella antibody testing uptake was relatively high (approximately 15%) in all three age groups soon after the distribution of the vouchers and then declined to below 2% during the second and third years. Further population-based approaches with continuous public engagement are required in workplaces to effectively promote and expand the rubella vaccination program in Japan.

12-year observation of tweets about rubella in Japan: A retrospective infodemiology study

Although rubella is an infectious disease that can be prevented by vaccination, there have been periodic epidemics in Japan, mainly among adult males. One of the reasons for this is the lack of interest in vaccination among the target adult male population. To clarify the reality of the discussion about rubella and provide basic resource for enlightening activities for rubella prevention, we collected and analyzed Twitter posts about rubella in Japanese between January 2010 and May 2022. We examined time series, number of tweets per account, tweeted contents, and retweet network. We found that the weekly number of rubella reports and the number of Twitter posts fluctuate simultaneously. During the 2018 rubella epidemic, the number of tweets increased due to the start of the rubella routine vaccination program and the use of cartoons to raise awareness. While 80% of the accounts posted three times or fewer during the period, some accounts posted multiple times per day for more than 12 years. Medical terms such as vaccines and antibodies were frequently used in the tweet contexts. In the retweet activity, a variety of actors, including mass media, medical professionals, and even rubella sufferers, contributed to disseminate rubella-related information.

Characteristics of participants in a public rubella antibody testing program conducted at a Japan professional football league venue

Background

Hypothesizing that soccer-associated public health campaigns influence men more than women, we investigated the characteristics and motivations of participants who received rubella antibody testing at a Japanese professional football league event.

Methods

This was a survey-based cross sectional study, comparing the characteristics and motivations between men and women regarding rubella antibody testing.

Results

Free and convenient testing was the biggest behavioral influencer, but the information provided by healthcare professionals and athletes also played a strong motivating role. Men reported more influence from celebrity athletes than women.

Conclusions

Public health attention raised by celebrity athletes may facilitate rubella awareness among male spectators.

Workplace factors associated with willingness to undergo human immunodeficiency virus testing during workplace health checkups

BACKGROUND

To examine workplace factors associated with willingness to undergo human immunodeficiency virus (HIV) testing during workplace health checkups.

METHODS

This cross-sectional study used an Internet-based self-administered questionnaire to obtain data from a pool of 24,287 Japanese workers. Binary and multiple logistic regression analyses evaluated the association between workplace factors and HIV testing. Data were adjusted for sex, age, marital status, education, and history of HIV testing.

RESULTS

We gathered information from 4,143 (17.1%) respondents, of whom 1,129 (27.3%) were willing to be tested for HIV as part of a workplace health checkup. The participants were 20-59 years old. Approximately half of the participants were male (49.9%), half were married (48.9%), and half had completed higher education (47.6%). Workplace hepatitis testing was offered to 15.6% of the respondents, and most participants underwent health checkups without their colleagues (52.1%) at a medical facility (60.2%). Willingness to undergo HIV testing was positively correlated with having an increased risk of occupational blood exposure (vs. not at risk, adjusted odds ratio [OR]: 1.74, 95% confidence interval [CI]: 1.41-2.15) or working in medical and welfare roles (vs. manufacturing, OR: 1.40, 95% CI: 1.07-1.84). The presence of occupational health staff at the workplace (vs. their absence, adjusted OR: 1.35, 95% CI: 1.16-1.59) and hepatitis testing (vs. not testing, adjusted OR: 2.02, 95% CI: 1.66-2.44) increased willingness to undergo HIV testing.

CONCLUSIONS

A pilot HIV-testing program involving individuals at an increased risk of occupational blood exposure and undergoing hepatitis tests in workplaces providing occupational health staff support is recommended.

Factors Predicting Rubella Vaccination and Antibody in Pregnant Women in Japan: A Report from Pregnant Women Health Initiative

This study aimed to identify the factors predicting rubella vaccination status based on self-reported data and the presence of sufficient rubella antibody titers in pregnant women in Japan. We used the results of the nationwide questionnaire survey conducted at obstetric facilities in the Pregnant Women Health Initiative Project (PWHI), with 23 participating hospitals recruiting pregnant women from June 2018–November 2019. We extracted age, the number of deliveries, educational level, household income, pre-pregnancy smoking, and knowledge of rubella from questionnaires and medical records. We analyzed the association of rubella vaccination status and antibodies with each of these factors. We found that the number of previous deliveries, educational level, annual household income, smoking before pregnancy, and knowledge of rubella were factors predicting self-reported rubella vaccination status, while age and the number of previous deliveries were identified as factors predicting the presence of sufficient rubella antibody titers (32 folds or higher). Women considering pregnancy should be immunized against rubella to prevent congenital rubella syndrome in the future. Furthermore, social policies are needed to strongly encourage vaccination, especially for all citizens who were not given the opportunity or missed the chance to be vaccinated against rubella.

Factors associated with adults' actions to confirm their own rubella immune status in Japan's drive toward rubella elimination: Cross-sectional online survey of non-healthcare workers in their 20s to 40s

Background

Rubella outbreaks occurred among adults in Japan in 2013-2014 and 2018-2019 due to immunity gaps. In response and aiming at rubella elimination by 2020, the government introduced countermeasures comprising supplementary immunization activities for voluntary testing of adult non-healthcare-related workers and vaccination of susceptible individuals. However, as of October 2020, rubella immunity testing and vaccination rates remained low. This study was conducted to identify factors associated with adults voluntarily confirming their rubella immune status, to help develop effective promotion activities for hard-to-reach and left-behind populations.

Methods

In this cross-sectional study, a general population sample of non-healthcare workers aged 20-49 years in Japan completed an online survey in November 2020. Univariate analysis was performed to examine associations of specific actions taken to confirm rubella immune status with social background characteristics, knowledge of rubella, and attitude to testing and vaccination. Log binomial regression analysis was performed to explore the associations following adjustment for social background characteristics.

Results

Among 1,854 respondents (927 men, 927 women), only 23.4% of men and 39.4% of women in their 20s to 40s have taken some action related to rubella prevention. Three major factors were associated with the targeted population having taken voluntary action: (1) knowing about testing for confirmation of immunity status (adjusted odds ratio [AOR] 4.29 men, 2.89 women), the rubella outbreak in 2013 among men in their 20s to 40s (AOR 2.79 men, 1.64 women), and congenital rubella syndrome (AOR 1.89 men, 3.10 women); (2) having acquaintances who were vaccinated against or tested for rubella (AOR 2.98 men, 1.95 women); and (3) having a positive attitude toward influenza vaccination (AOR 2.48 men, 1.83 women). Marriage, desire for pregnancy, and having children were weakly associated with taking action.

Conclusions

Currently, insufficient voluntary action is being taken by high-risk adult populations to close the identified immunity gaps. In this last mile to rubella elimination, our findings and suggested potential interventions via annual health check-ups and occupational health and public health initiatives could prove helpful in developing further countermeasures that actively promote and implement supplementary immunization activities targeting all adult generations.

Gender differences in the determinants of willingness to get the COVID-19 vaccine among the working-age population in Japan

Many factors are related to vaccination intentions. However, gender differences in the determinants of intention to get the coronavirus disease 2019 (COVID-19) vaccine have not been fully investigated. This study examined gender differences in the determinants of willingness to get the COVID-19 vaccine among the working-age population in Japan. We conducted a cross-sectional study of Japanese citizens aged 20-65 years using an online self-administered questionnaire in December 2020. Logistic regression analysis was performed. Among 27,036 participants (13,814 men and 13,222 women), the percentage who were willing to get the COVID-19 vaccine was lower among women than among men (33.0% vs. 41.8%). Age and education level showed a gender gap regarding the association with willingness to get the COVID-19 vaccine: men who were older or had a higher level of education were more willing to get the vaccine, whereas women aged 30-49 years and those with a higher level of education showed a relatively low willingness to get the vaccine. For both men and women, marriage, higher annual household income, underlying disease, current smoking, vaccination for influenza during the current season, and fear of COVID-19 transmission were linked to a higher likelihood of being willing to get the COVID-19 vaccine. These findings give important insight into identifying target groups in need of intervention regarding COVID-19 vaccination, especially among women. Providing education about COVID-19 and influenza vaccination in the workplace may be an effective strategy to increase COVID-19 vaccine uptake.